An endoscope is a medical instrument used for examining and treating internal body parts such as the alimentary canals, airways, the gastrointestinal system, and other organ systems. Conventionally used endoscopes have at least a flexible tube carrying a fiber optic light guide for directing light from an external light source situated at a proximal end of the tube to a distal tip. Also, most endoscopes are provided with one or more channels, through which medical devices, such as forceps, probes, and other tools, are passed. Further, during an endoscopic procedure, fluids, such as water, saline, drugs, contrast material, dyes, or emulsifiers are often introduced or evacuated via the flexible tube. A plurality of channels, one each for introduction and suctioning of liquids, may be provided within the flexible tube.
Endoscopes have attained great acceptance within the medical community since they provide a means for performing procedures with minimal patient trauma while enabling the physician to view the internal anatomy of the patient. Over the years, numerous endoscopes have been developed and categorized according to specific applications, such as cystoscopy, colonoscopy, laparoscopy, and upper GI endoscopy among others. Endoscopes are usually inserted into the body's natural orifices or through an incision in the skin.
In many endoscopes the distal end of an insertion tube is capable of being articulated by a steering mechanism that includes a pair of external control wheels coupled to steering cables mounted inside the insertion tube. Rotation of one of the control wheels produces an up or down deflection of the distal tip of the insertion tube while rotation of the second control wheel produces a left or right deflection of the insertion tube tip. By operating the two control wheels, the distal end of the insertion tube can be pointed at a desired target within the range of the instrument or maneuvered through a tortuous path of travel.
Further, the control wheels or knobs are locked through respective braking mechanisms, thereby causing the distal end of the insertion tube to be fixed in a desired position.
For example, German patent application DE 20 2011 109 769 U1, filed on Jul. 1, 2011 and assigned to the applicant of the present specification, discloses an endoscope having an articulation unit. The deflection of the articulation unit (also called curvature device), and thus of the distal end of the endoscope is effected by means of cables. In each case, two cables arranged opposite each other on the outer circumference of the articulation unit are connected to form a cable pair. The cable pairs are attached in such a way to cable drums that can be adjusted by rotary knobs so that the distal end of the articulation unit carries out a movement upwards or downwards (up/down; U-D) or a movement in a direction right or left (right/left; R-L).
When a human body is examined using an endoscope having an articulation unit, on occasions it can be advantageous to fix the deflection of the articulation unit. As mentioned, usually this is accomplished by means of a locking device, also called a brake, that prevents the cable drum(s) from rotating.
Known braking or locking devices often are of a complicated design. What is needed is an efficient braking system that enables an operating physician to easily fix the endoscope insertion tube tip in a desired position when required and just as easily move the tip in a desired direction.
There is therefore a need for a system that ensures smooth directional readjustment of right and left (or up and down) movement of the insertion tube tip after applying a brake for fixing the end position. There is also need for a watertight braking system that provides a complete separation of free movement and locking operations.